Dear Daisy Dog: My 8-year-old, 25-pound (healthy weight) cocker spaniel tore the anterior cruciate ligament (ACL) in his knee. He takes two supplements for his joints: Dasuquin and fish oil. What do you think about treating his torn ACL with crate rest rather than surgery?

Daisy responds: The anterior cruciate ligament, often called the cranial cruciate ligament (CrCL) in dogs, helps stabilize the knee. Partial tears and complete ruptures of the CrCL are the most common cause of hind leg lameness in dogs.

CrCL disease is most prevalent in large-breed, overweight dogs older than 4 years of age. Obesity quadruples the risk of CrCL rupture.

The most prominent clinical sign is lameness, which may range from mild, intermittent limping to holding the leg up because the knee is so painful and unstable that it cannot bear any weight.

Conservative treatment is effective at resolving lameness within four months in up to 86 percent of dogs weighing less than 33 pounds. Conservative treatment requires crate rest, restricted activity, weight control, anti-inflammatory pain medication and joint supplements like those you give your dog.

On the other hand, fewer than 20 percent of dogs over 33 pounds respond to conservative therapy. These dogs require surgical stabilization of the knee.

It seems reasonable to try conservative therapy before deciding whether to sign your dog up for surgery.

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Dear Christopher Cat: My friend's cat, Wobbly, has poor coordination and falls over because of a disease called CH. What is CH? Can I inadvertently take it home and infect my cat?

Christopher responds: CH, or cerebellar hypoplasia, is a condition marked by incomplete (hypo-) development (-plasia) of the cerebellum, the part of the brain that coordinates movement.

Clinical signs, which become obvious when the kitten starts walking, include poor balance and coordination, exaggerated movements, swaying, a wide stance and tremors. The condition is not painful, and cats with CH have a normal lifespan.

CH arises when the kitten is exposed to the feline distemper virus before birth or within two weeks after birth, while the cerebellum is still developing. This may occur if the kitten's mother is exposed to other cats with this contagious virus or even if she is vaccinated for distemper during this time.

Fortunately, Wobbly can't transmit CH to another cat, and you can't carry the disease home with you. Therefore, don't hesitate to visit your friend and her cat.

No treatment reverses CH, so affected cats must live indoors. The degree of disability remains constant throughout life, although cats with CH do learn to compensate.

Ask the Vet's Pets appears Friday. The animal authors of the column live with Lee Pickett, V.M.D., who practices companion animal medicine. Contact them at www.askthevetspets.com.